1. Technical Field
The present disclosure relates to optical elements and, particularly, to a spacer and a lens module using the spacer.
2. Description of Related Art
In related art, a lens module includes a first lens, a second lens, and a spacer. The spacer is disposed between the first lens and the second lens and for blocking off-axis light rays to avoid aberrations. The spacer is typically annular and includes a cylindrical inner surface, and defines a chamfer facing an object-side end of the lens module to efficiently reflect off-axis light rays. The lens module is typically assembled manually. However, to reduce a total size of the lens module, the spacer is small, for example, an outer diameter of the spacer may be reduced to about 2 mm, and a width of the chamfer may be reduced to about 0.1 mm, such that it is difficult to indentify a proper orientation of the spacer such that chamfer faces the object-side end of the lens module by manual visual inspections.
Therefore, it is desirable to provide a spacer, which can overcome the limitations described.